Maintenance of Primary Hepatocyte Functions In Vitro by Inhibiting Mechanical Tension-Induced YAP Activation

Summary: Hepatocytes are the primary functional cells of the liver, performing its metabolic, detoxification, and endocrine functions. Functional hepatocytes are extremely valuable in drug discovery and evaluation, as well as in cell therapy for liver diseases. However, it has been a long-standing challenge to maintain the functions of hepatocytes in vitro. Even freshly isolated hepatocytes lose essential functions after short-term culture for reasons that are still not well understood. In the present study, we find that mechanical tension-induced yes-associated protein activation triggers hepatocyte dedifferentiation. Alleviation of mechanical tension by confining cell spreading is sufficient to inhibit hepatocyte dedifferentiation. Based on this finding, we identify a small molecular cocktail through reiterative chemical screening that can maintain hepatocyte functions over the long term and in vivo repopulation capacity by targeting actin polymerization and actomyosin contraction. Our work reveals the mechanisms underlying hepatocyte dedifferentiation and establishes feasible approaches to maintain hepatocyte functions. : It has been a long-standing challenge to maintain the functions of hepatocytes in vitro. Sun et al. find that mechanical tension-induced Yap activation triggers hepatocyte dedifferentiation. Alleviation of mechanical tension by confining cell spreading or treatment with a small molecule cocktail targeting actin/actomyosin dynamics could maintain hepatocyte functions. Keywords: hepatocytes, dedifferentiation, small molecules, mechanical tension